Proposal: Wallet SDK Payment Lifecycle Completeness

Development Fund Proposal Submission

Proposal file: wallet-sdk-payment-lifecycle.md

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Summary

The wallet team is building Utility Registry token pre-approvals now. Once that lands, three gaps become the next real problem for any wallet using it: pre-approvals expire silently, there is no unified read path for transaction history across registries, and there is no standard way for one Canton wallet to request a payment from another. This proposal closes all three as a single scope — payment lifecycle completeness for the wallet SDK.

Scope: pre-approval expiry tracking and renewal; unified multi-registry transfer history; Canton payment request URI format with SDK parser and builder. All contributed upstream to canton-network/wallet. 600,000 CC over 3 milestones, 19 weeks.

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Checklist

• [x] Proposal file added under /proposals/
• [x] Milestones and funding amounts defined
• [x] Acceptance criteria included
• [x] Alignment with Canton priorities described

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Notes for Reviewers

The pre-approval expiry and history gaps are direct follow-ons to the pre-approval work currently in progress. The payment request format fills the interoperability gap that appears the moment two wallets both implement the transfer path — without a shared URI format there is no way for them to exchange payment requests. The spec is proposed as a CIP so any wallet can implement it independently.